This invention relates to an insect trap. More specifically, it relates to a trap that uses suction to draw insects into the trap.
Suction-type insect traps are well known in the art. A suction source, such as a fan, is used to draw large amounts of air through a trap, snaring any insects that are entrained in the air flow. However, without an effective system for attracting insects to the trap, only an unlucky few insects that happen to be within range of the suction source will be caught by the trap. The prior art teaches the use of heat, water vapor and carbon dioxide as insect lures, as these are all present in the breath and sweat of warm-blooded animals. Octanol is also known as a chemical insect attractant. It is believed that the temperature of the exhaust stream is important, and should be above ambient temperature but not exceed 115xc2x0 F.
Effective prior art suction traps use a combination of suction, heat, water vapor and chemical attractants to lure insects, especially mosquitoes, to the trap. A suction inlet surrounds an outlet stream containing the various attractants. Insects follow the attractant plume to the trap, and are drawn into a long suction tube that surrounds an exhaust tube. Once inside the trap, the insects are caught in a net located under the combustion unit. Exhaust from the combustion unit supplies the heat, carbon dioxide and water vapor to the air, which is then exhausted from the unit through the exhaust tube. A tiny cartridge inside the exhaust tube holds supplemental chemical attractants.
Counter-current air flow of the exhaust within the intake air poses several design problems. There is limited space over the length of the counter flow to deposit and hold the insects. The trap area is often located under the combustion engine. To empty the trap, or check how full it is, the user must inconveniently open the housing and move the engine platform aside. After emptying the trap, the engine is returned to its original position and the housing closed before normal operation is resumed.
An additional problem with the air flow arrangement in the known trap is the limited number of locations on the device that supplemental chemical attractants can be positioned. Attractants are available in a number of different forms, sizes and strengths. However, the limited amount of space within the exhaust tube limits the user to the form or strength dictated by the size of the chemical receptacle.
Counter-current flow is very efficient at transferring heat between two streams, but this can also be a disadvantage at times. The intake air is always at ambient temperature, while the exhaust stream is always warmer than ambient, providing heat transfer from the exhaust tube to the intake air. Because the heat content of the two streams is interrelated, it may be more difficult to control the exhaust temperature. For example, on a hot day, there may be insufficient heat transfer from the exhaust to the intake stream to cool the exhaust stream to below 115xc2x0 F.
The air flow pattern of the known design also makes it more costly to manufacture due to the number of parts that have to be separately molded and assembled. This means that many molds have to be made, additional labor is needed to make and assemble the parts and additional warehouse space is needed to store the additional parts until the insect trap is assembled. If the engine is designed to be moveable, additional parts are needed compared to a stationary engine.
There is a need in the art for an effective insect trap that is more convenient for the user, yet is reasonably priced. There is also a need for an insect trap which addresses the air flow issues discussed above.
The insect trap of the present invention has an improved air flow pattern. Emptying insects from the unit is easy and convenient for the user. Multiple sizes or types of chemical attractant can be used in the unit, and are conveniently placed. Even with these advantages, the present trap uses relatively few molded parts and requires little assembly, resulting in a trap that is reasonably priced.
More specifically, the present insect trap apparatus includes a trap housing having at least one inlet and at least one outlet. A source of suction is located within the housing and is in fluid communication with the inlet for drawing insects through the inlet. Carbon dioxide gas is disposed in the housing and includes a combustion chamber with a chamber outlet. An exhaust system is connected to the CO2 gas source for directing a flow of CO2 from the gas source to the at least one outlet. Insects are caught in a trap cup that is connected to the housing and disposed between the inlet and the source of suction.
Air flow through this insect trap overcomes many of the disadvantages of the prior art. Without the limitations of counter flow between the intake air and the exhaust, the air flow can be directed through areas of the trap so that insects can be trapped where they are conveniently accessed by the user for disposal. Versatility in air flow also allows receptacles for supplemental attractants to be conveniently placed in areas where there is space for multiple receptacles to accommodate a variety of attractant sizes or types.
Without heat exchange between the intake air and the exhaust, independent control of the two fluid streams makes it easier to control the temperature of the exhaust gas outflow. Although the temperatures of all of the fluid streams will vary with the temperature of the ambient air, temperature is expected to be more easily controlled where there are fewer opportunities to transfer heat.
The structure of the present insect trap also makes it more economical to manufacture. Conduits for fluid transfer are molded into other structural elements, providing fewer parts that need to be molded, stored and assembled. Less labor can be used since fewer parts are made and assembled. The cost of making the molds is reduced. Thus, the present insect trap can be more efficiently made, resulting in savings to both the manufacturer and the consumer.